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dbe3ba3018
This patch contains basic ftrace support for LoongArch. Specifically, function tracer (HAVE_FUNCTION_TRACER), function graph tracer (HAVE_ FUNCTION_GRAPH_TRACER) are implemented following the instructions in Documentation/trace/ftrace-design.txt. Use `-pg` makes stub like a child function `void _mcount(void *ra)`. Thus, it can be seen store RA and alloc stack before `call _mcount`. Find `alloc stack` at first, and then find `store RA`. Note that the functions in both inst.c and time.c should not be hooked with the compiler's -pg option: to prevent infinite self-referencing for the former, and to ignore early setup stuff for the latter. Co-developed-by: Jinyang He <hejinyang@loongson.cn> Signed-off-by: Jinyang He <hejinyang@loongson.cn> Signed-off-by: Qing Zhang <zhangqing@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
97 lines
2.2 KiB
ArmAsm
97 lines
2.2 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* LoongArch specific _mcount support
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*
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* Copyright (C) 2022 Loongson Technology Corporation Limited
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*/
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#include <asm/export.h>
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#include <asm/ftrace.h>
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#include <asm/regdef.h>
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#include <asm/stackframe.h>
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.text
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#define MCOUNT_S0_OFFSET (0)
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#define MCOUNT_RA_OFFSET (SZREG)
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#define MCOUNT_STACK_SIZE (2 * SZREG)
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.macro MCOUNT_SAVE_REGS
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PTR_ADDI sp, sp, -MCOUNT_STACK_SIZE
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PTR_S s0, sp, MCOUNT_S0_OFFSET
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PTR_S ra, sp, MCOUNT_RA_OFFSET
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move s0, a0
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.endm
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.macro MCOUNT_RESTORE_REGS
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move a0, s0
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PTR_L ra, sp, MCOUNT_RA_OFFSET
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PTR_L s0, sp, MCOUNT_S0_OFFSET
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PTR_ADDI sp, sp, MCOUNT_STACK_SIZE
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.endm
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SYM_FUNC_START(_mcount)
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la.pcrel t1, ftrace_stub
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la.pcrel t2, ftrace_trace_function /* Prepare t2 for (1) */
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PTR_L t2, t2, 0
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beq t1, t2, fgraph_trace
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MCOUNT_SAVE_REGS
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move a0, ra /* arg0: self return address */
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move a1, s0 /* arg1: parent's return address */
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jirl ra, t2, 0 /* (1) call *ftrace_trace_function */
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MCOUNT_RESTORE_REGS
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fgraph_trace:
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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la.pcrel t1, ftrace_stub
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la.pcrel t3, ftrace_graph_return
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PTR_L t3, t3, 0
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bne t1, t3, ftrace_graph_caller
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la.pcrel t1, ftrace_graph_entry_stub
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la.pcrel t3, ftrace_graph_entry
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PTR_L t3, t3, 0
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bne t1, t3, ftrace_graph_caller
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#endif
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SYM_INNER_LABEL(ftrace_stub, SYM_L_GLOBAL)
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jr ra
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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SYM_INNER_LABEL(ftrace_graph_func, SYM_L_GLOBAL)
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bl ftrace_stub
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#endif
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SYM_FUNC_END(_mcount)
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EXPORT_SYMBOL(_mcount)
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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SYM_FUNC_START(ftrace_graph_caller)
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MCOUNT_SAVE_REGS
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PTR_ADDI a0, ra, -4 /* arg0: Callsite self return addr */
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PTR_ADDI a1, sp, MCOUNT_STACK_SIZE /* arg1: Callsite sp */
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move a2, s0 /* arg2: Callsite parent ra */
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bl prepare_ftrace_return
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MCOUNT_RESTORE_REGS
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jr ra
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SYM_FUNC_END(ftrace_graph_caller)
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SYM_FUNC_START(return_to_handler)
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PTR_ADDI sp, sp, -2 * SZREG
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PTR_S a0, sp, 0
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PTR_S a1, sp, SZREG
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bl ftrace_return_to_handler
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/* Restore the real parent address: a0 -> ra */
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move ra, a0
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PTR_L a0, sp, 0
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PTR_L a1, sp, SZREG
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PTR_ADDI sp, sp, 2 * SZREG
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jr ra
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SYM_FUNC_END(return_to_handler)
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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